US1788485A - Means for preventing pitting, corrosion, and scale formation - Google Patents

Description

Jan. 13, 1931. L. o. GUNDERSON MEANSFOR PREVENTING FITTING, CORROSION, AND SCALE FORMATION Filed Oct. :51, 1927 3 Sheets-Sheet 1 Jan. 13, 1931. 1.. 0;. GUNDERSON MEANS FOR PREVENTING FITTING, CORROSION, AND SCALE FORMATION Filed Oct. 31, 1927 3 Sheets-Sheet 2 F3. k E w (Q N m w! 5! 3 H Q RE N 1' Q a Q) Lew 23' Q @unaemon WWW o. GUNDERSON 1,788,485

MEANS F'OR PREVENTING FITTING, CORROSION, AND SCALE FORMATION Jan. 13, 1931'.

Filed Oct. 31, 192'? 3 Sheets-Sheet 3 ZZZ/Z Lem: 0.524224149215022 ill \\I 0 of making such electrodes and their asso Patented Jan. 13, 1931 UNITED STATES LEWIS O. GUNDERSON, OF BLOOMING'I'ON, ILLINOIS MEANS FOR PREVENTING FITTING, CORROSIO N, AND SCALE FORMATION Application filed October 31, 1927. Eerial No. 230,03 3.

This invention relates in general to improvements in the means for the prevention of pitting, corrosion and scale formation in steam boilers, condensers and the like and is in general related to the subject matter of my Patent No. 1,449,991, the present invention relating to improvements in the electrodes employed for this purpose and to improvements in the construction and method anti-pitting, anti-corrosion method, the metallic portion of the steam generating device, or the like, to which the system is applied must be effectually insulated to prevent impairment of its eificiency due to decomposition or disintegration of the .electrodes themselves while submerged in the water of the boiler, and also that the insulating material employed in this connection must be highly resistant to decomposition,

fracture and other structural and physical defects which might be caused by the effects of high temperature. and pressure.

The present invention includes, as one of its improvements, the provision ,of an insulating material which, while dense in form and highly resistant to fracture, is at the same time sufliciently tenacious so that expansion and contraction of the parts associated therewith will not cause fracture or undesirable distortion of the insulating material.

This invention further has, as an object,

the provision of an improved electrode structure, and insulating material therefor, char acterized by high resistance to decomposition and disintegration under high temperatures and pressures; the provision of an improved form of ele2trode and metallic and insulating structures therefor which are highly reslstant to the effects of high temperatures and pressures; the provision of an improved method of applying an insulating material to an electrode or other metallic electric conductor; the provision of an improved form of insulating structure for a metallic conductor characterized by hardness and tenacity to a degree permitting expansion and'contraction of the metallic parts without fracture of the non-metallic or insulating parts; and the provision of an electrode of" the character referred to, which may be conveniently installed in position in asteam boiler, appurtenance thereto, pipe line, or the like, without material alteration in the structure of the boiler or pipe line.

PATENT OFFICE It will be understood that my invention a has, therefore, as important features thereof, the properties of high resistance to fracture, or other undesirable distortion for indefinite periods, due to the effects of high steam pressure and high temperature, and especially finds utility in rendering efiicient service when applied to locomotive boilers wherein considerable place.

The foregoing and such other objects and vadvantages as may appear or be pointed out as this description proceeds are attained in the structural embodiments illustrated in the accompanying drawings in which:

Figure 1 is a fragmentary elevational and partly sectional view of a locomotive boiler showing my invention applied thereto.

Figure 2' is a transverse sectional View taken on the line 22 of Figure 1 looking in the'direction indicated by the arrows.

Figures 3 and 4: are enlarged side and end elevational views of the form of the invention shown in Figures 1 and 2.

Figure 5 is a circuit diagram as employed in connection with my invention.

Figure 6 is a view somewhat similar to Figure 1 showing an alternative form of the invention.

Figure 7 is an enlarged sectional view of one of the electrodes employed in the structure shown in Figure 1.

Figure 8 is a fragmentary elevational strains and vibrations take I view of the form of the electrode employed in the structure shown in Figure 6.

Figure 9 is a perspective View of a half cylinder employed in connection with the construction of parts of my invention.

Figure 10 is a sectional view of a stationary boiler of the water tube type showing my invention applied thereto. v

Figure 11 is a vertical sectional view taken on the line 1111 of Figure 10 looking in the direction indicated by the arrows.

Figure 12 is a fragmentary sectional view of a pipe line showing one form of my invention applied thereto.

It will be understood, upon reference to my patent aforesaid, that the method of counteracting local galvanic action or pitting and corrosion generally, as well as scale formation in steam boilers and the like, involves the provision of a means for setting up an electric current of small magnitude,

within the boiler by the provision of a suitable source of electric current. This current flows from a generator, or other source of current, into the boiler water which thereby becomes an electrolyte, the boiler shell, tubes, and other metallic parts becoming a cathode, suitable anodes being employed and disposed at advantageous points within the boiler.

T have found that in the application of my invention (Patent No. 1,449,991) to a locomotive boiler, the high temperature and the extreme vibration and strains to which such r a boiler is exposed in service cause an early breaking down of all of the insulating materials known tome prior to discovery of my present invention.

' Referring now more particularly tothe drawings and as to the structure shown in Figures 1 to 4 and 7, I have illustrated a steam boiler of the locomotive type, designated 10. This boiler has the usual fire box 11, smoke box 12 and fire tubes 13 extending between the front and rear closure plates 14 and 15 of the boiler.

As an advantageous arrangement of the electrodes within the boiler which serve as anodes, I provide a horizontally extending metallic tube 16, which may be a one-inch iron pipe, secured rigidly on the shell of the boiler out of contact with any of the metal parts thereof by the provision of brackets 17, 17 which are provided with seats 18 and clamping portions 19 which encircle insulating cylinders 20 surrounding the tube (anode) for fixedly retaining the same in place. The insulating cylinder 20 is of the same material as I hereinafter describe as employed in the leading-in portions of the electrodes. The anodes 16 may be disposed at advantageous points within the boiler so as to best counteract corrosion and scale formation. These anodes are connected by the supporting and conducting structure's,

generally designated 21, 21, and electric conduit 22 to the positive side of the generator 23 which may be the headlight generator of the locomotive.

As shown in Figure 5, the generator has the negative side thereof connected, as at 24, to the boiler, and the positive side is connected by a conductor 25 to the conductors 26 and 27 through suitable resistance coils 28 and 29, respectively, to provide the desired voltage and current.

The structures 21, shown in Figures 1 and 2, are in detailbest shown in Figure 7. In Figure 7 a portion of the shell 10 is shown, and for the purpose of mounting the electrodes in position, I provide a threaded opening 10a disposed in the shell at the desired convenient point. This threaded opening receives the threaded shank 30 of a metallic casing 31 which latter is provided with a bore 32 annularly enlarged at 33 and internally threaded, as at 34. The enlargement of the bore forms a shoulder 35 against which abuts a packing washer, of suitable material, 36. This washer may be of a compressible material, suitable as steam packing, which will provide a steam and watertight joint, and facilitate retention of the electrode. The casing is closed by a gland member 37 which engages the threads 34, and suitable compressible packing washer, 38, is provided, also a metallic washer 38a against which said gland engages.

The electrode itself includes a metallic conducting portion 39 of suitable length to extend without the casing 31 through this casing and into the boiler a suflicient distance to connect with the anode 16. The conducting portion 39 is provided with a annular enlargement 40, and the conducting portion 39 is externally knurled or otherwise roughened, as at 41, and is covered substantially from end to end, with the exception of the threaded portions 42 and 43, with a coating 44 of insulating material, this coating being molded under high pressure and temperature on to the conductor 39 and, furthermore, to the shape in general of said conductor. An annular enlargement 45 thus is formed, which enlargement is clamped by the washers 36 and 38 owing to their compression by the gland 37, thus fixedly retaining the electrode in position in the casing. It will be observed that the bore 32 is slightly larger than the electrode and this permits of a small degree of flexing of the electrode and its insulating material without fracture whenthe boiler is in service and is subjected to the tortiona-l vibrations occurring in locomotive boilers.

The outer end of the conductor 39, that is, the threaded portion 43, projects beyond the insulating coating and receives the nuts 46 and 47 by which a connection is made to the conductor 48 which may be one of the conductors 26 or 27. It will also be noted that the gland 37 preferably loosely engages the portion 49 of the insulating coating to permit flexing of the electrode and its insulating covering where it passes through the gland.

The inner threaded projection 42 of the conductor 39 is provided with a tee or other fitting 50 which engages by threaded connection of the anode tube 16 so that this tube is, fixedly mounted at a desired position in the boiler.

The insulating material which I have found 'to give the best results for the purpose of an insulating coating, as shown, is a phenol-formaldehyde condensation product combined with asbestos fibre or mica mixed in such proportions that, when set and hardened, the structure is sufficiently hard to resist early decomposition in the presence of high temperature, pressures, and in the presence of steam and water and yet possessing a degree of flexibility, tenacity and strength which will prevent thehardened insulating" covering from becoming easily fractured. In forming the electrode the phenol formaldehyde condensation product'with asbestos fibre such as bakelite-asbestos molding material, obtainable in the open market, is placed with the metallic conductor part of the electrode in a specially designed mould, whereupon the mould is closed and subjected to a pressure of approximately two thousand pounds per squareinch at 350 F. which auses a setting of the insulating material in a form which increases its tenacity and" strength.

, The insulating cylinders which I prefer to employ for supportingthe anode 16 may he formed in a special mould and-is best shown in Figure 9, and includes two half cylinders, only one of which, namely 51, is shown. The half cylinder as moulded is provi dcd with a tongue 52' on one straight edge and a groove 52a on the other straight edge thereof in such manner that when the two half cylinders are fitted together the tongues and grooves will complementally engage,-

thus forming ,a cylinder which surrounds the anode member 16, fixedly retaining same in place. I claim that this feature of my invention is novel, that is, the application of bakelite-asbestos composition moulded about the onducting member under high pressure and relatively high temperature to produce an insulating material which resists the deleterious action of boiler water and steam, that is, resists the action of high temperature and pressure to a greater extent than is obtained through any other insulating substances heretofore made and known to me. Of course, it will be understood that a specially shaped mould will be required for forming the insulating coating shown in Figure 7 wherein the enlargement 45 must be provided for. y

In Figure 8, another form of the electrode is shown, the conductor 39a being secured in the boiler shell 10 by the same form of construction as that shown in Figure 7, the inner end of the conductor 39a being in threaded engagement with a metal bushing 53 cast in a ball 54 which latter is preferably constructed of a metallic material known as duriron, a well known alloy readily obtainable in the open market and having high resistance to the action of acids and other corroding agents, as well as electrolysis. I find that this alloy serves my purpose best as being permanently indestructible, and permits of a relatively small anode being employed.

The installation of suchan anode is shown at 55, 55 in Figure 6 wherein the anodes are installed at advantageous pointsin the boiler shell 10?) shown in this figure. Between the insulating covering 39 and the ball 54 I interpose a washer 53a preferably formed of rubber asbestos which prevents the electrolyte from reaching the conductor 39a at this affords, though in' some instances it may be desirable to employ the form of anode shown in Figures 6 and 8. The latter is highly satisfactory for use in pipe lines, condensers and other apparatus inwhich the space available for the installation of the electrode is limited or wherein the device is to be applied to a boiler constructed in such a manner as to render impracticable an electrode such as indicated at 16. It will be observed that in knurling'or roughening the surface of the metallic conductor and then applying the insulating covering, I am'enabled to prevent longitudinal relative movement, sometimes called creeping, between the electrode and the insulating material. Furthermore, should the insulating covering which I employ become cracked, more or less, there is yet sufficient tenacity and strength in the covering to prevent chipping thereof, and it will be observed that, should cracking occur, oxygen generated at the anode will readily and quickly fill such cracks by the formation therein of oxides, and, therefore, the electrode will continue to be of use in spite of the damage inflicted; While I have suggested the employment of flaked mica in combination with the penol formaldehyde condensation product (bakelite) I have found it is desirable to employ the asbestos material, 'owingto the cost of th'e'flaked mica, for

' water tubes. The device of my invention here takes a form similar to that shown in Figure 1, that is, the anode is an iron pipe, as

indicated at 63, and is supported in brackets 64:, 64 disposed in the header 70. These brackets may be constructed similarly to those shown in Figures 3 and 4 and may be provided with insulating cylinders 65, 6:?

formed of the insulating material referred to herein.

At one end of the anode 63 l provide a coupling 66 and to this is connected a conductor 390 which is similar to the conductor 39 referred to hereinabove. This conductor 39c passes through a supporting insulating structure 67 substantially similar in construction to that of the device shown in Figure 7, and a suitable conductor 68 conducts current to the external projecting portion of the electrode 39c.

in order to insure that the protection will be afforded in the water spaces 61 and 62, provide 'T-couplings 68 and 69 from which depend electrodes 71 and 72 which extend into and lie in spaced relation to the walls of the water spaces 61 and 62. Suitable brackets 73 and 74, similar to those indicated at 66L and 65, support the depending electrodes 71 and 72 and are rovided with insulating cyilnders 75 and 6. It will be observed that any other desired shape may be given to the electrodes 63, 71 and 72 in order that an adequate surface of contact will be offered to the electrode to insureprotection against pitting, corroding or other deleterious effects in these vital portions or the boiler.

Referring to the alternative form of the invention shown in Figure 12, l have illus trated a pipe line 77 serving to conduct steam, hot water, or other fluid in which an electrolytic action is likely to take place. Here the electrodes are shown at 7 8, 78 and any number of the electrodes desired may be installed simply by boring the desired number of holes in the pipe line. The nature of the electrode is such that it does not materially interfere with the flow of fluid through the pipe line and yet ollers sufficient surface of contact to prevent deleterious effects due to the electrolytic action of the fluid flowing through said pipe. lhe form of the invention shown in Figure 8 will be employed in the installation shown in Figure 12, that is, the ball construction, it being understood, however, that the supporting casing shown in Figure 7 will be employed for supporting the electrode 78 in this form of the invention. In

area res view of the detailed description of the electrodes of Figures 7 and 8 it is not believed necessary to describe this structure again in detail as applied to the pipe line, a "further application of the same having been already shown and described in Figure 6.

I desire to emphasize that the application of the anode shown in Figure 12, wherein the exposed metallic portion of the electrode is the material known as duriron, permits of the employment of a relatively small electrode yet giving suflicient surface of contact, the nature of this material being that it affords an anode which is indestructible and substantially permanent and makes such an application of the invention to pipe lines practicable.

I claim:

1. in combination with a liquid container, an electrode for employment therein including a metallic core having an insulating covering, said core and covering having an enlargement between the ends, a metallic projection at on end of said core, a metallic casing threaded into said container and encompassing said enlargement, and means in said casing for retaining said electrode in position in said container.

2. In combination with a liquid container, an electrode for employment therein including a metallic core having an insulating covering moulded thereon under pressure, said core and covering having an enlargement bctween the ends, a metallic projection at one end of said core, a metallic casing threaded into said container and encompassing said enlargement, and means in said casing for retaining said electrode in position in said container.

3. In combination with a liquid container, an electrode for employment therein including a metallic core having an insulating covering, said core and-covering having an enlargement between the ends, a metallic projection at one end of said core, a metallic casing threaded into said container and encompassing said enlargemenhand means in said casing for sealing the casing and for retaining said electrode in position in said container. Y

l. In combination with a liquid container, an electrode for employment therein includinga metallic core having an insulating covering, said core and covering having an enlargement between the ends, a metallic projection at one end of said core, a threaded apertured enlargement on the inner end of said core, a metallic element connected to and supported by said metallic enlargement, a

metallic casing threaded into said container and encompassing said enlargement, and means in said casing for retaining said electrode in position in said container.

5. An electrode including a metallic core having an enlarged portion between its ends a and an insulating material therefor which is moulded about said core to substantially conform to the shape thereof and a metallic separable housing engaging said enlarged portion for supporting said electrode.

6. The combination with a steam boiler, ineluding water spaces and a water header, of an anode for employment in said spaces, and header, including a metallic conductor extending longitudinally of said header submerged in the liquid contained therein, and extensions on said conductor lying within said water spaces surrounded by the water contents thereof.

7. In an electrode, the combination of a metallic core and a moulded insulated material surrounding said core, said core having a projecting threaded portion extending from said insulating material, an electrode adapted to form an anode, including a substantially bore-like member constructed of duriron and having a metallic threaded socket for engage ment with the threaded extension of said metallic core.

8. In an electrode, the combination of a metallic core and a moulded insulated material surrounding said core, said core having a projecting threaded portion extending from said insulating material, an electrode adapted to form an anode including a substantially bore-like member constructed of duriron and having a metallic threaded socket for engage ment with the threaded extension of said metallic core, and insulating means interposed between said bore and the insulating covering "of said core.

9. In combination with a steam boiler or the like, having an external shell, an anode applied in said boiler and including a longitudinally extending conductor formed of iron pipe or rod, brackets on said shell for supporting said conductor, insulating means between said brackets and said conductor and supporting the latter in spaced relation to said shell, and means extending through the shell of the boiler and connected to said iron pipe or rod for supplying electrical ener thereto.

In testimony whereof I a x my signature at 10 So. La Salle Street, Chica 0, Illinois.

LEWIS O. GUND RSON.

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